Steel Buildings in Europe

Part 2: Concept Design 2 - 37 Figure 4.11 Composite floors create a safe working platform during construction 4.6.4 Installation of precast concrete slabs Placing of precast concrete slabs b ecomes difficult if they are lowered through erected steelwork. Better practice is to place the s labs as the steelwork for each floor is erected, and for the supply and in stallation to be part of the Steelwork Contractor’s package. Generally, columns and f loor steelwork will b e erected, with minimal steelwork at upper levels su fficient to stabilise the columns, until the precast slabs have been positioned. Steelwork for the upper floors will then continue. 4.7 Structure – service integration Most large office-type structures require air conditioning or ‘comfort cooling’, which will necessita te both horizo ntal a nd ve rtical dis tribution syste ms. The provision f or such system s is of critical im portance for the superstructur e layout, affecting the layout and type of members chosen. The basic d ecision either to integ rate the ductwork within the stru ctural depth or to sim ply suspend the ductwork at a lower lev el affects the ch oice o f member, the fire protection system, the cladding (cost and program me) and overall building height. Other system s provide conditioned air from a raised floor. The most commonly used systems are the Variable Air Volume system (VAV) and the Fan Coil system . VAV systems are often used in buildings with single owner occu piers, b ecause of their lower runnin g costs. Fan Coil system s are often used in speculative buildings because of their lower capital costs.